Oh, you think that the arbitrary line your draw in your own life determines the standard for being moral? Well, welcome to the club with the rest of us. Its easy to make an argument that shifts the blame away from Meta - they offer a product that is completely optional, its up to the individual person whether to use it or not, so working for Meta is not immoral. Thats a line someone could draw in their own life, and there isn't a single argument you can make based in any sort of grounded framework for them being wrong.
Once you find a solid counter argument to "its a product that people are free not to use", then we can have a conversation.
Anyway, I think I've said all I possibly can to educate you. I hope you can take something from it.
TLDR, if you can do that much mental gymastics, you can probably do the same to justify you taking the Meta job.